Planar phase shifter for use in the microwave range

ABSTRACT

A planar phase shifter for use in the microwave range which comprises a meander-like microstrip conductor which is provided on a non-magnetic ferrite substrate, and a gyromagnetic body being provided at a distance from the microstrip conductor to reduce attenuation of the microwave due to losses in the gyromagnetic material.

1 Med States Patent 1 1 1 1 3,838,363

Sehilz 1 Sept. 24, 1974 [54] PLANAR PHASE SHIFTER FOR USE IN THE 3,448,410 6/1969 Parks 333/241 X MICROWAVE RANGE 3,585,536 6/1971 Braginski et a1. 333/31 R [75] Inventor: Wolfram Schilz, Norderstedt,

Germany Primary Examiner-:Paul L. Gensler [73] Assignee: U.S. Philips Corporation, New Attorney, Agent, or Firm-Frank R. Trifari York, NY.

[22] Filed: May 29, 1973 [21] Appl. No.: 364,521 [57] ABSTRACT [30] Foreign Application Priority Data A planar phase shifter for use in the microwave range June 19, 1972 Germany 2229668 which Comprises a meander-like miCIOSIFiP Conductor which is provided on a non-magnetic ferrite substrate, 52 us. c1. 333/24.1, 333/84 M and gywmagnetic y being Provided at distance [51 Int. Cl. .1101], 1/32 from the microstrip conductor to reduce attenuation 58 Field 01 Search 333/241, 24.2, 31 R of the microwave due to losses in the gyromagnetic material.

[56] References Cited UNITED STATES PATENTS 3 Claims, 4 Drawing Figures 3,447,143 5/1969 Hair et a1 333/24.1 X A ,GROUND PLANE Pmmmwz 3338.363

sum in? 2 3 GYROMAGNETIC J/FER'RITE PLANAR PHASE SHIFTER FOR USE IN THE MICROWAVE RANGE The invention relates to a planar phase shifter comprising a meander-like microstrip line which is provided according to the microstrip technique on a substrate, and also comprising a gyromagnetic body.

Phase shifters of this kind which can be controlled continuously (analog) phase shifters or digitally are often used in the microstrip technique. In particular for the construction of phased aerial arrays, in which the bundled microwave beam is electrically deflected, a large number of phase shifters is required. Some of the essential apsects for the usability of the phase shifters in such systems are small dimensions and low losses.

A phase shifter of this kind is known from US. Pat. No. 3,418,605. Therein, the meander line can be provided on a gyromagnetic substrate as well as on a nonmagnetic substrate. In the latter case, the ferrite is provided on the side of the meander line which is remote from the substrate. When a microwave is applied to the meander line, a circularly polarized high-frequency field is generated by the coupling of fields of adjoining line segments, the said circularly polarized field being used for the realization of given phase shifts. This is because the microwave is coupled by the circular field to the gyromagnetic material which, for example, is used as the substrate, the said gyromagnetic material being prepolarized by an adjustable static magnetic field. The effective permeability u of the material is dependent of the strength of the static magnetization of the substrate and of the direction of this magnetization with respect to the direction of propagation of the microwave.

By continuous variation of the magnetization of, for example, a soft-magnetic ferrite material which is used as the gyromagnetic material, a continuous phase shift (analog phase shifter) can thus be achieved, or a discontinuous phase shift (latching phase shifter) can be obtained by the switching over of the remanent magnetization of hard-magnetic ferrites which are used as the gyromagnetic materials.

One of the drawbacks of these phase shifters is their comparatively high loss.

The invention has for its object to provide a substantial reduction of the attenuation of such a phase shifter.

The phase shifter according to the invention is characterized in that the gyromagnetic body and the microstrip line are arranged at some distance from each other.

The invention will be described in detail hereinafter with reference to the figures.

FIG. 1 is a perspective view of an embodiment of a phase shifter according to the invention,

FIG. 2 is a cross-sectional view of an embodiment of a phase shifter according to the invention,

FIGv 3 shows the attenuation as a function of the distance between the meander line and the gyromagnetic body of the embodiment shown in FIG. 2, and

FIG. 4 shows the differential phase shift as a function of the distance between the meander line and the gyromagnetic body of the embodiment shown in FIG. 2.

Referring to FIGS. 1 and 2, a meander l (microstrip) is provided on a non-magnetic substrate 2 above which ferrite cores or blocks 3, used as the gyromagnetic material, are arranged. By introducing a clearance between the meander line and the ferrite cores 3, for example, by means of a Teflon foil 4, the attenuation of the microwave which is caused by the magnetic material can be substantially reduced, without the phase shift per meander length being substantially affected.

In FIG. 3 the attenuation a is plotted in dB as a function of the thickness of the Teflon layer 4, and in FIG. 4 the differential phase shift Ad) is plotted in degrees as a function of the thickness of the Teflon layer for the phase shifter shown in FIG. 2. As appears from these graphs, a substantial reduction of the attenuation a is obtained with a thickness of 0.05 mm of the Teflon layer, without the differential phase shift being significantly affected.

The phase shift of the individual cores can be adapted by a slight modification of the position of the ferrite cores 3 with respect to the meander line 1 and- /or by changing the distance between them.

A non-magnetic ferrite such as for example ZnF O is advantageously used as the substrate, and a Mg-Mn ferrite is advantageously used for the switching cores 3.

What is claimed is:

1. A planar phase shifter for use in the microwave range, comprising a non-magnetic substrate, a meander-like microstrip line arranged on said substrate, at least one gyromagnetic body having a plane parallel to said microstrip line, said body being magnetizable by a static magnetic field to provide a coupling with very high frequency magnetic fields resulting in the microstrip line meanders when a microwave is applied thereto, and spacing means of non-magnetic insulating material for supporting said body at a distance from said microstrip line to reduce the attenuation of the microwave due to losses in the gyromagnetic body.

2. A planar phase shifter as claimed in claim 1, characterized in that said spacing means is an insulating foil of a dielectric material.

3. A planar phase shifter as claimed in claim 1 wherein said gyromagnetic body is of Mg-Mn ferrite.

l UNITED STATES-PATENT OFFICE I CERTIFICATE OF CORRECTION Patent No. 3, 38,363 I r a d September 24, 1974. I Inventorfib WOLFRAM S'CHILZ It is certified that error appears in the above-identified patent andthat; said Letters Patent are hereby corrected as shown below:

On the title'pag e, Seqtipn. [30] change "22296 68" to Signed and sealed this 3rd day of December 1974'.

(SEAL) Arrest:

McCOY M. GIBSON JR. C. MARSHALL DANN Commissioner of Patents Attesting Officer 

1. A planar phase shifter for use in the microwave range, comprising a non-magnetic substrate, a meander-like microstrip line arranged on said substrate, at least one gyromagnetic body having a plane parallel to said microstrip line, said body being magnetizable by a static magnetic field to provide a coupling with very high frequency magnetic fields resulting in the microstrip line meanders when a microwave is applied thereto, and spacing means of non-magnetic insulating material for supporting said body at a distance from said microstrip line to reduce the attenuation of the microwave due to losses in the gyromagnetic body.
 2. A planar phase shifter as claimed in claim 1, characterized in that said spacing means is an insulating foil of a dielectric material.
 3. A planar phase shifter as claimed in claim 1 wherein said gyromagnetic body is of Mg-Mn ferrite. 